Weird Law in South Dakota any wide spot in the road can have a "casino". the definition of a casino is "X" number of slot machines (which I can't remember the exact numbers but it's around 20).

So there's 100's of bar/convenience store/casinos in South Dakota.

This is the same law that makes things "odd" in Deadwood.....where you will can walk between casinos and not know that you just entered another casino (casinos are connected an open entry way so they can have more slot machines between them).